A Katyusha rocket landed inside the Khor Mor gas field in Sulaymaniyah in northern Iraq on Wednesday but caused no damage, the city's counter-terrorism service said.
The Pearl Consortium, United Arab Emirates energy firm Dana Gas and its affiliate, Crescent Petroleum, have the rights to exploit Khor Mor and Chemchemal, two of the biggest gas fields in Iraq.
No group claimed responsibility, but armed groups that some Iraqi officials say are backed by Iran have claimed similar attacks in the past.
A source with knowledge of the matter also said there was no damage or impact on operations as a result of the attack. Three people were injured, two security sources said.
The security sources told Reuters earlier that a Katyusha rocket hit the headquarters of Dana Gas in the Iraqi province of Kirkuk.